1NCDU(1) ncdu manual NCDU(1)
2
6 ncdu - NCurses Disk Usage
7
9 ncdu [options] dir
10
12 ncdu (NCurses Disk Usage) is a curses-based version of the well-known
13 'du', and provides a fast way to see what directories are using your
14 disk space.
15
17 Mode Selection
18 -h, --help
19 Print a short help message and quit.
20 -v, -V, --version
22 Print ncdu version and quit.
23 -f FILE
25 Load the given file, which has earlier been created with the "-o"
26 option. If FILE is equivalent to "-", the file is read from
27 standard input.
28 For the sake of preventing a screw-up, the current version of ncdu
30 will assume that the directory information in the imported file
31 does not represent the filesystem on which the file is being
32 imported. That is, the refresh, file deletion and shell spawning
33 options in the browser will be disabled.
34 dir Scan the given directory.
36 -o FILE
38 Export all necessary information to FILE instead of opening the
39 browser interface. If FILE is "-", the data is written to standard
40 output. See the examples section below for some handy use cases.
41 Be warned that the exported data may grow quite large when
43 exporting a directory with many files. 10.000 files will get you an
44 export in the order of 600 to 700 KiB uncompressed, or a little
45 over 100 KiB when compressed with gzip. This scales linearly, so be
46 prepared to handle a few tens of megabytes when dealing with
47 millions of files.
48 -e, --extended, --no-extended
50 Enable/disable extended information mode. This will, in addition to
51 the usual file information, also read the ownership, permissions
52 and last modification time for each file. This will result in
53 higher memory usage (by roughly ~30%) and in a larger output file
54 when exporting.
55 When using the file export/import function, this flag will need to
57 be added both when exporting (to make sure the information is added
58 to the export), and when importing (to read this extra information
59 in memory). This flag has no effect when importing a file that has
60 been exported without the extended information.
61 This enables viewing and sorting by the latest child mtime, or
63 modified time, using 'm' and 'M', respectively.
64 --ignore-config
66 Do not attempt to load any configuration files.
67 Scan Options
69 These options affect the scanning progress, and have no effect when
70 importing directory information from a file.
71 -x, --one-file-system
73 Do not cross filesystem boundaries, i.e. only count files and
74 directories on the same filesystem as the directory being scanned.
75 --cross-file-system
77 Do cross filesystem boundaries. This is the default, but can be
78 specified to overrule a previously given "-x".
79 --exclude PATTERN
81 Exclude files that match PATTERN. The files will still be displayed
82 by default, but are not counted towards the disk usage statistics.
83 This argument can be added multiple times to add more patterns.
84 -X FILE, --exclude-from FILE
86 Exclude files that match any pattern in FILE. Patterns should be
87 separated by a newline.
88 --include-caches, --exclude-caches
90 Include (default) or exclude directories containing CACHEDIR.TAG.
91 The directories will still be displayed, but their contents will
92 not be scanned or counted towards the disk usage statistics.
93 <http://www.brynosaurus.com/cachedir/>
94 -L, --follow-symlinks, --no-follow-symlinks
96 Follow (or not) symlinks and count the size of the file they point
97 to. As of ncdu 1.14, this option will not follow symlinks to
98 directories and will count each symlinked file as a unique file
99 (i.e. unlike how hard links are handled). This is subject to
100 change in later versions.
101 --exclude-firmlinks, --follow-firmlinks
103 (MacOS only) Exclude or follow firmlinks.
104 --include-kernfs, --exclude-kernfs
106 (Linux only) Include (default) or exclude Linux pseudo filesystems,
107 e.g. /proc (procfs), /sys (sysfs).
108 The complete list of currently known pseudo filesystems is: binfmt,
110 bpf, cgroup, cgroup2, debug, devpts, proc, pstore, security,
111 selinux, sys, trace.
112 Interface options
114 -0 Don't give any feedback while scanning a directory or importing a
115 file, other than when a fatal error occurs. Ncurses will not be
116 initialized until the scan is complete. When exporting the data
117 with "-o", ncurses will not be initialized at all. This option is
118 the default when exporting to standard output.
119 -1 Similar to "-0", but does give feedback on the scanning progress
121 with a single line of output. This option is the default when
122 exporting to a file.
123 In some cases, the ncurses browser interface which you'll see after
125 the scan/import is complete may look garbled when using this
126 option. If you're not exporting to a file, "-2" is probably a
127 better choice.
128 -2 Provide a full-screen ncurses interface while scanning a directory
130 or importing a file. This is the only interface that provides
131 feedback on any non-fatal errors while scanning.
132 -q, --slow-ui-updates, --fast-ui-updates
134 Change the UI update interval while scanning or importing. Ncdu
135 will update the screen 10 times a second by default
136 ("--fast-ui-updates"), this can be decreased to once every 2
137 seconds with "-q" or "--slow-ui-updates". This feature can be used
138 to save bandwidth over remote connections. This option has no
139 effect when "-0" is used.
140 --enable-shell, --disable-shell
142 Enable or disable shell spawning from the browser. This feature is
143 enabled by default when scanning a live directory and disabled when
144 importing from file.
145 --enable-delete, --disable-delete
147 Enable or disable the built-in file deletion feature. This feature
148 is enabled by default when scanning a live directory and disabled
149 when importing from file. Explicitly disabling the deletion feature
150 can work as a safeguard to prevent accidental data loss.
151 --enable-refresh, --disable-refresh
153 Enable or disable directory refreshing from the browser. This
154 feature is enabled by default when scanning a live directory and
155 disabled when importing from file.
156 -r Read-only mode. When given once, this is an alias for
158 "--disable-delete", when given twice it will also add
159 "--disable-shell", thus ensuring that there is no way to modify the
160 file system from within ncdu.
161 --si, --no-si
163 List sizes using base 10 prefixes, that is, powers of 1000 (KB, MB,
164 etc), as defined in the International System of Units (SI), instead
165 of the usual base 2 prefixes, that is, powers of 1024 (KiB, MiB,
166 etc).
167 --disk-usage, --apparent-size
169 Select whether to display disk usage (default) or apparent sizes.
170 Can also be toggled in the browser with the 'a' key.
171 --show-hidden, --hide-hidden
173 Show (default) or hide "hidden" and excluded files. Can also be
174 toggled in the browser with the 'e' key.
175 --show-itemcount, --hide-itemcount
177 Show or hide (default) the item counts column. Can also be toggled
178 in the browser with the 'c' key.
179 --show-mtime, --hide-mtime
181 Show or hide (default) the last modification time column. Can also
182 be toggled in the browser with the 'm' key. This option is ignored
183 when not in extended mode (see "-e").
184 --show-graph, --hide-graph
186 Show (default) or hide the relative size bar column. Can also be
187 toggled in the browser with the 'g' key.
188 --show-percent, --hide-percent
190 Show (default) or hide the relative size percent column. Can also
191 be toggled in the browser with the 'g' key.
192 --sort COLUMN
194 Change the default column to sort on. Accepted values are disk-
195 usage (the default), name, apparent-size, itemcount or mtime. The
196 latter only makes sense in extended mode, see "-e".
197 The column can be suffixed with -asc or -desc to set the order to
199 ascending or descending, respectively. e.g. "--sort=name-desc" will
200 sort by name in descending order.
201 --group-directories-first, --no-group-directories-first
203 Sort (or not) directories before files.
204 --confirm-quit, --no-confirm-quit
206 Require a confirmation before quitting ncdu. Very helpful when you
207 accidentally press 'q' during or after a very long scan.
208 --confirm-delete, --no-confirm-delete
210 Require a confirmation before deleting a file or directory. Enabled
211 by default, but can be disabled if you're absolutely sure you won't
212 accidentally press 'd'.
213 --color SCHEME
215 Select a color scheme. The following schemes are recognized: off to
216 disable colors, dark for a color scheme intended for dark
217 backgrounds and dark-bg for a variation of the dark color scheme
218 that also works in terminals with a light background.
219 The default is dark-bg unless the "NO_COLOR" environment variable
221 is set.
222
224 Ncdu can be configured by placing command-line options in
225 "/etc/ncdu.conf" or "$HOME/.config/ncdu/config". If both files exist,
226 the system configuration will be loaded before the user configuration,
227 allowing users to override options set in the system configuration.
228 Options given on the command line will override options set in the
229 configuration files. The files will not be read at all when
230 "--ignore-config" is given on the command line.
231 The configuration file format is simply one command line option per
233 line. Lines starting with "#" are ignored. Example configuration file:
234 # Always enable extended mode
236 -e
237 # Disable file deletion
239 --disable-delete
240 # Exclude .git directories
242 --exclude .git
243
245 ? Show help + keys + about screen
246 up, down, j, k
248 Cycle through the items
249 right, enter, l
251 Open selected directory
252 left, <, h
254 Go to parent directory
255 n Order by filename (press again for descending order)
257 s Order by filesize (press again for descending order)
259 C Order by number of items (press again for descending order)
261 a Toggle between showing disk usage and showing apparent size.
263 M Order by latest child mtime, or modified time. (press again for
265 descending order) Requires the -e flag.
266 d Delete the selected file or directory. An error message will be
268 shown when the contents of the directory do not match or do not
269 exist anymore on the filesystem.
270 t Toggle dirs before files when sorting.
272 g Toggle between showing percentage, graph, both, or none. Percentage
274 is relative to the size of the current directory, graph is relative
275 to the largest item in the current directory.
276 c Toggle display of child item counts.
278 m Toggle display of latest child mtime, or modified time. Requires
280 the -e flag.
281 e Show/hide 'hidden' or 'excluded' files and directories. Please note
283 that even though you can't see the hidden files and directories,
284 they are still there and they are still included in the directory
285 sizes. If you suspect that the totals shown at the bottom of the
286 screen are not correct, make sure you haven't enabled this option.
287 i Show information about the current selected item.
289 r Refresh/recalculate the current directory.
291 b Spawn shell in current directory.
293 Ncdu will determine your preferred shell from the "NCDU_SHELL" or
295 "SHELL" variable (in that order), or will call "/bin/sh" if neither
296 are set. This allows you to also configure another command to be
297 run when he 'b' key is pressed. For example, to spawn the vifm(1)
298 file manager instead of a shell, run ncdu as follows:
299 export NCDU_SHELL=vifm
301 ncdu
302 Ncdu will set the "NCDU_LEVEL" environment variable or increment it
304 before spawning the shell. This variable allows you to detect when
305 your shell is running from within ncdu, which can be useful to
306 avoid nesting multiple instances of ncdu. Ncdu itself does not
307 (currently) warn when attempting to run nested instances.
308 q Quit
310
312 Entries in the browser interface may be prefixed by a one-character
313 flag. These flags have the following meaning:
314 ! An error occurred while reading this directory.
316 . An error occurred while reading a subdirectory, so the indicated
318 size may not be correct.
319 < File or directory is excluded from the statistics by using exclude
321 patterns.
322 > Directory is on another filesystem.
324 ^ Directory is excluded from the statistics due to being a Linux
326 pseudo filesystem.
327 @ This is neither a file nor a folder (symlink, socket, ...).
329 H Same file was already counted (hard link).
331 e Empty directory.
333
335 To scan and browse the directory you're currently in, all you need is a
336 simple:
337 ncdu
339 If you want to scan a full filesystem, your root filesystem, for
341 example, then you'll want to use "-x":
342 ncdu -x /
344 Since scanning a large directory may take a while, you can scan a
346 directory and export the results for later viewing:
347 ncdu -1xo- / | gzip >export.gz
349 # ...some time later:
350 zcat export.gz | ncdu -f-
351 To export from a cron job, make sure to replace "-1" with "-0" to
353 suppress any unnecessary output.
354 You can also export a directory and browse it once scanning is done:
356 ncdu -o- | tee export.file | ./ncdu -f-
358 The same is possible with gzip compression, but is a bit kludgey:
360 ncdu -o- | gzip | tee export.gz | gunzip | ./ncdu -f-
362 To scan a system remotely, but browse through the files locally:
364 ssh -C user@system ncdu -o- / | ./ncdu -f-
366 The "-C" option to ssh enables compression, which will be very useful
368 over slow links. Remote scanning and local viewing has two major
369 advantages when compared to running ncdu directly on the remote system:
370 You can browse through the scanned directory on the local system
371 without any network latency, and ncdu does not keep the entire
372 directory structure in memory when exporting, so you won't consume much
373 memory on the remote system.
374
376 Every disk usage analysis utility has its own way of (not) counting
377 hard links. There does not seem to be any universally agreed method of
378 handling hard links, and it is even inconsistent among different
379 versions of ncdu. This section explains what each version of ncdu does.
380 ncdu 1.5 and below does not support any hard link detection at all:
382 each link is considered a separate inode and its size is counted for
383 every link. This means that the displayed directory sizes are incorrect
384 when analyzing directories which contain hard links.
385 ncdu 1.6 has basic hard link detection: When a link to a previously
387 encountered inode is detected, the link is considered to have a file
388 size of zero bytes. Its size is not counted again, and the link is
389 indicated in the browser interface with a 'H' mark. The displayed
390 directory sizes are only correct when all links to an inode reside
391 within that directory. When this is not the case, the sizes may or may
392 not be correct, depending on which links were considered as "duplicate"
393 and which as "original". The indicated size of the topmost directory
394 (that is, the one specified on the command line upon starting ncdu) is
395 always correct.
396 ncdu 1.7 and later has improved hard link detection. Each file that has
398 more than two links has the "H" mark visible in the browser interface.
399 Each hard link is counted exactly once for every directory it appears
400 in. The indicated size of each directory is therefore, correctly, the
401 sum of the sizes of all unique inodes that can be found in that
402 directory. Note, however, that this may not always be same as the space
403 that will be reclaimed after deleting the directory, as some inodes may
404 still be accessible from hard links outside it.
405
407 Directory hard links are not supported. They will not be detected as
408 being hard links, and will thus be scanned and counted multiple times.
409 Some minor glitches may appear when displaying filenames that contain
411 multibyte or multicolumn characters.
412 All sizes are internally represented as a signed 64bit integer. If you
414 have a directory larger than 8 EiB minus one byte, ncdu will clip its
415 size to 8 EiB minus one byte. When deleting items in a directory with a
416 clipped size, the resulting sizes will be incorrect.
417 Item counts are stored in a signed 32-bit integer without overflow
419 detection. If you have a directory with more than 2 billion files,
420 quite literally anything can happen.
421 On macOS 10.15 and later, running ncdu on the root directory without
423 `--exclude-firmlinks` may cause directories to be scanned and counted
424 multiple times. Firmlink cycles are currently (1.16) not detected, so
425 it may also cause ncdu to get stuck in an infinite loop and eventually
426 run out of memory.
427 Please report any other bugs you may find at the bug tracker, which can
429 be found on the web site at https://dev.yorhel.nl/ncdu
430
432 Written by Yoran Heling <projects@yorhel.nl>.
433
435 du(1)
436ncdu-1.18 2022-11-30 NCDU(1)